BELDEN NAMAH: As a true citizen of this country, as a patriot, as a nationalist, I have given instructions to file this particular matter in court.

LIAM FOX: For him this issue is not just about the law; it's about post-colonial politics.

BELDEN NAMAH: It is so sad that Papua New Guinea continues to say yes master to our colonial masters.

LIAM FOX: On Friday Mr Namah's lawyer Loani Henao filed a summons in the National Court in Port Moresby.

It seeks a declaration that the memorandum of understanding signed by the Australian and PNG governments last year to establish the processing centre is unconstitutional.

Mr Henao says the MOU is unlawful because it deprives asylum seekers sent to Manus Island of their personal liberty.

LOANI HENAO: Those personal liberties can be restricted or restrained by the government of this country if the foreigners have entered unlawfully. The refugees, they did not break any laws. The laws in fact were breached by the government of this country.

LIAM FOX: The summons asks the court to permanently restrain the PNG government from continuing to detain people at the centre.

It also seeks a temporary injunction preventing any more asylum seekers being sent to Manus Island while the case is heard.

PNG's attorney-general Kerenga Kua has said asylum seekers have effectively consented to their detention because they knew what was in store for them when they left their home countries.

Mr Henao scoffs at that line of reasoning.

LOANI HENOU: Who would like to be detained if he or she has not committed any offence? It looks like they had no choice. Is that freedom? I will respectfully submit that it is not.

IAN RINTOUL: It's a shame I think that it's been Papua New Guinea law that might put an end to at least one half of the Pacific solution and that under present Australian law we haven't got the mechanisms to mount a challenge.

LIAM FOX: Ian Rintoul from the Refugee Action Coalition says the challenge is timely because the situation on Manus Island is becoming increasingly grim.

LIAM FOX: Manus Island is not quite at meltdown but it's not far from it. The hunger strike has been continuing, we've seen a series of quite serious self-harm incidents, quite a number of attempted suicides.

From the Archives

Around 500 Indigenous people fought in the First World War, and as many as 5,000 in the second. But many Aboriginal and Torres Strait Islander diggers who made it home received little or no recognition for their contribution. On Anzac Day, 2007, the first parade to commemorate their efforts and bravery was held in Sydney. Listen to our report from that day by Lindy Kerin.